Rename Pandas DataFrame Index
I've a csv file without header, with a DateTime index. I want to rename the index and column name, but with df.rename() only the column name is renamed. Bug? I'm on version 0.12.0
In [2]: df = pd.read_csv(r'D:\Data\DataTimeSeries_csv//seriesSM.csv', header=None, parse_dates=[[0]], index_col=[0] )
In [3]: df.head()
Out[3]:
1
0
2002-06-18 0.112000
2002-06-22 0.190333
2002-06-26 0.134000
2002-06-30 0.093000
2002-07-04 0.098667
In [4]: df.rename(index={0:'Date'}, columns={1:'SM'}, inplace=True)
In [5]: df.head()
Out[5]:
SM
0
2002-06-18 0.112000
2002-06-22 0.190333
2002-06-26 0.134000
2002-06-30 0.093000
2002-07-04 0.098667
Answer
The rename method takes a dictionary for the index which applies to index values.
You want to rename to index level's name:
df.index.names = ['Date']
A good way to think about this is that columns and index are the same type of object (Index or MultiIndex), and you can interchange the two via transpose.
This is a little bit confusing since the index names have a similar meaning to columns, so here are some more examples:
In [1]: df = pd.DataFrame([[1, 2, 3], [4, 5 ,6]], columns=list('ABC'))
In [2]: df
Out[2]:
A B C
0 1 2 3
1 4 5 6
In [3]: df1 = df.set_index('A')
In [4]: df1
Out[4]:
B C
A
1 2 3
4 5 6
You can see the rename on the index, which can change the value 1:
In [5]: df1.rename(index={1: 'a'})
Out[5]:
B C
A
a 2 3
4 5 6
In [6]: df1.rename(columns={'B': 'BB'})
Out[6]:
BB C
A
1 2 3
4 5 6
Whilst renaming the level names:
In [7]: df1.index.names = ['index']
df1.columns.names = ['column']
Note: this attribute is just a list, and you could do the renaming as a list comprehension/map.
In [8]: df1
Out[8]:
column B C
index
1 2 3
4 5 6